Conventionally, there is a three-dimensional scanner that measures a three-dimensional shape of an object (for example, see Japanese Patent Laid-open Publication No. H07-270137). This three-dimensional scanner, for example, emits a slit-shaped light beam to a measuring object while changing an irradiation position with respect to the measuring object and sequentially captures images of the measuring object irradiated with the light beam by a camera.
Next, the three-dimensional scanner detects the position of the light beam in an image by reading out image information on the captured image from photodetectors of the camera and scanning all pixels of the captured image.
Then, the three-dimensional scanner measures the three-dimensional shape of the measuring object by calculating the height of each portion of the measuring object by the principle of triangulation using an irradiation angle and an acceptance angle of the light beam and the distance from a light source of the light beam to the camera.